pfQuizzz: Linux - Chinese characters

I'm not very familiar with Linux and never tried to run pfQuizzz on Linux myself. However, from what you wrote it seems to me that the problem might be related to the default font that pfQuizzz uses for its dialogs (maybe the one on Ubuntu doesn't support Chinese characters by default). So I would suggest trying to change the dialog font.

It can be done by going to:GoTo / Setup, and checking[x] Use Custom Font

Then select:Chose Custom Fontand try to find a font that supports Chinese characters(You might also want to experiment a bit with the Script option)